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When to Plant Thai Basil in Union County, NM

Thai basil has a distinctive anise-licorice flavor with sturdy purple stems and small leaves. It is essential in Thai, Vietnamese, and other Southeast Asian cuisines.

Union County, New Mexico is in USDA Zone 5b. The average last spring frost is April 30 and the first fall frost is October 9, giving you a growing season of approximately 162 days.

At an elevation of 6,384 feet, Union County receives approximately 17.5 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 85ยฐF, providing good warmth for Thai Basil during the growing season. Sandy soil warms quickly in spring โ€” great for early planting โ€” but Thai Basil will need more frequent watering and organic matter to retain nutrients. With low rainfall, drip irrigation is essential for growing Thai Basil successfully. Mulch heavily to conserve soil moisture.

Union County, NM (Zone 5b) Moderate season
162 days
Last Spring Frost April 30
162 growing days
First Fall Frost October 9

Union County Soil Profile

Soil Type

Sandy Loam

Soil pH

6.9-8.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (30 days to spare)
Start indoors: Mar 7 Transplant: May 9 🍅 Harvest: Jul 4 – Sep 5
Recommended (50%) ✓ Fits season (29 days to spare)
Start indoors: Mar 12 Transplant: May 14 🍅 Harvest: Jul 9 – Sep 10
Safe Start (90%) ✓ Fits season (27 days to spare)
Start indoors: Mar 29 Transplant: May 31 🍅 Harvest: Jul 26 – Sep 27

Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.5″/week
You supply
1.0″/week
Watering frequency 2-3 times/week
Season total 1,464 gal / 100 sq ft
Drought risk

Water stress score is 10/10 โ€” consider drought-tolerant varieties and mulching

Thai Basil needs ~859 GDD — county provides 2,227 GDD Excellent fit

Thai Basil Planting Timeline โ€” Union County, NM

Thai Basil Planting Calendar

Activity When Date Range
Start Indoors March 12 Mar 12 โ€“ Mar 26
Transplant Outdoors May 14 May 14 โ€“ May 28
Direct Sow May 7 May 7 โ€“ May 28
Harvest July 9 Jul 9 โ€“ Sep 10

Plant 0.5" deep ยท 8" apart ยท Rows 12" apart

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March Start Indoors
April โ€”
May Transplant Outdoors Direct Sow
June โ€”
July Harvest
August Harvest
September Harvest
October โ€”
November โ€”
December โ€”

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

50โ€“75 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 5b

Growing Season

162 days

Growing Tips for Union County

Start seeds indoors or direct sow after last frost. Thai basil holds up better to heat in cooking than sweet basil. Pinch flowers to prolong leaf production.

Companion Planting

Good Companions

Avoid Planting Near

  • Rue
  • Sage

Level Up Your Garden

Frequently Asked Questions

When should I plant Thai Basil in Union County, NM?

Union County is in Zone 5b with an average last frost of April 30. Plan your Thai Basil planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Union County, NM?

Union County, New Mexico is in USDA Hardiness Zone 5b. The average last spring frost is April 30 and first fall frost is October 9.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Union County gardeners in Zone 5b organize planting dates, track what's growing, and never miss a planting window.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Union County, NM. Local conditions may vary. Last updated: April 2026.